I'm noticing some differences between the accessible stop (wheelchair boarding) situation at our agency and the ability of GTFS/GTFS+ to specify those differences. Specifically:
- There are stops which are technically legally accessible from an ADA standpoint but which we don't recommend that people needing ADA access use because they present physical challenges.
- There is a stop that is accessible to accessible streetcar trips but not to accessible bus trips. This means that accessible trips to this accessible stop cannot provide accessibility.
- There are several stops that are accessible to accessible bus trips but not to accessible streetcar trips.
- Pertinent to the previous two items, we occasionally have unscheduled replacements of one or more streetcar trips with bus trips. These are not reflected in the GTFS file.
As for the abilities of the GTFS and GTFS+ files to record these:
stops.txt has a wheelchair boarding field with 3 values:
0/empty - no info
1 - some vehicles can board wheelchairs here
2 - no vehicles can board wheelchairs here
trips.txt has a wheelchair accessible field with 3 values:
0/empty - no info
1 - vehicle can accommodate at least one wheelchair on this trip
2 - no riders in wheelchairs can be accommodated on this trip
stop_times.txt has no information about accessibility
Deficiencies as follows:
- No way to indicate that a stop is accessible if the rider insists but that it is better if the rider chooses a different stop. This could be handled with additional field values.
3 - Stop is accessible under the ADA but may present challenges to use.
- No way to indicate that a particular accessible stop is accessible for a particular accessible trip. This could be handled with an optional accessibility override value in the stop_times file.
0/empty - no override
1 - this stop is accessible for this trip
2 - even if this stop is accessible for some vehicles and the vehicle for this trip is accessible, this stop is not accessible for this trip/vehicle
4 - this stop is normally accessible for this trip; there is the possibility of the stop not being accessible on this trip due to vehicle substitution, even if the substitute vehicle is accessible
Additionally, the case of the stop not being accessible on a particular trip due to vehicle substitution could be handled by an additional field in StopTimeUpdate, perhaps WheelchairRelationship:
SCHEDULED Accessible or not in accordance with the GTFS file.
NOT ACCESSIBLE Even if this stop is normally accessible for this trip, it will not be accessible for this trip.
ACCESSIBLE Even if this stop is normally not accessible for this trip, it will be accessible for this trip.
NO_DATA No data is given for this stop.
With regard to San Francisco's Market Street island stops:
Accessible to historic streetcars (F-line streetcar trips) but not to
buses (F-line bus substitution trips, all other routes):
Accessible to buses (F-line bus substitution trips, all other routes) but not to historic streetcars (F-line streetcar trips):
- Inbound, Market @ 9th
- Inbound, Market @ 6th
- Outbound, Market @ 2nd
- Outbound, Market @ Larkin/Hayes
All remaining Market Street island stops are either accessible to all vehicle types or not accessible to any vehicle type, and are therefore outside the scope of this post.